#include<stdio.h>
#include<stdlib.h>
int main()
{
     int i,j;
     int x=0;
     int y=5;
     
	 int velocity_x=1;
	 int velocity_y=1;
     int left=0;
	 int right=20;
	 int top=0;
     int bottom=10;

     while(1)
     {
          x=x+velocity_x; 
		  y=y+velocity_y; 
		  
          system("cls");
          
          for(i=0;i<x;i++)
               printf("\n");
          for(j=0;j<y;j++)
               printf(" ");
          printf("o");
          printf("\n");
          
          if((x==top) || (x==bottom))
               velocity_x=-velocity_x;
          if((y==left) || (y==right))
               velocity_y=-velocity_y;
     }
     return 0;
}
